Method of treating cane-juice.



E. W. DEMING.

METHOD OF TREATING CANE JUICE.

APPLICATION FILED JUNE s. 1909.

997,605, Patented July 11,1911.

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EUGENE 'W'. DEMING, OF ,NEW YORK, N. Y., ASSIGNQR TO DEMING-APPARATUS COMPANY, OF YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD OF TREATING CANE-JUICE.

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Specification of Letters Patent.

Patented July it, 19111.

Application filed June 3, 1909. Seriat No. 499,975.

To all whom it may concern:

Be it known that I, EUGENE W. DEMING,

. a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Methods of Treating Cane-Juice, of which the following is a specification.

The object of this invention is the provision of a method whereby cane juices may be defecated and decolorized in a continuous manner and more efficiently and eco-.

' clarified by the successive use of lime and sulfur dioxid, the' efi'ect of the lime being to produce a bulky precipitate of calcium salts of various orgamc acids, and that of sulfur dioxid'being o bleach the juices. The ac tionof sulfur dioxid on the coloring matters derived from the rindis however comparativelyslight and is essentially temporary .in

character, the color re-appearing in the subsequent treatment of the juices and syrups.

As a result, the syrups and masse-cuites are yellow or brown and ordinarily yield a grade of sugar known to the trade as yellow clarifiedi A modifieddefecation process heretofore practiced consists in adding to the juices, after the usual liming a' small proportion of a com aratively weak mineral acid, phosphoric acld' being usually employed. This is added in presence of the lime or calcium recipitate, and in large part .enters immediately into combination forming. an insoluble calciumphosphate which is removed with the scums: its use in;this .manner has not been found appreciably more efi'ective than that of sulfur dioxid. If however an acid-of this character be added to the cleared or clarified juices from which theyca lcium precipitate has been removed, its efi'ectiveness in de-- stroying the coloring matters is greatly enhanced. According to the present invention such acid employed under conditions affording. the highest efliciency, not only in the decolo'ri-z'i'ng of the juice, but in the removal of suspended impurities which even in mi-. nute proportions have amost injurious effect upon the-* grade or quality of the sugar. Juices defecated and decolorized as hereinafter described are found in practice to be capable of yielding a high grade of marketable sugars even from highly colored raw juices, the treatment being continuous in character and not involving the necessity of filtering the entire body of juice.

I prefer to proceed substantially as follows: The raw juice from the mills is strained as usual and limed, the proportion of lime being usually sufficient completely to neutralize the acids of the juice, and prefer-' ably in very slight excess of this proportion. Sulfur di'oXid may be applied to' the cold juice, but its use is not necessary to the process. The juice is next heated under pressure in a continuous flow heater which may be of the character described in my prior patents, being usually raised to a temperature somewhat exceeding the atmospheric boiling point, and is then preferably-treated to effect the removal of the dissolved gases, which would otherwise slowly separate from the liquid and attach themselves to and buoy up a considerable proportion of the preci itate. This elimination of the gases is best e ected by subjecting thejuices proceeding from the heater in a suitable closed vessel to reduce pressure, as described in 'my copending application, Sen No. 426,900, filed April 13, 1908.". The gas-free juice passes thence to' a closed continuous-ilow separating or settling tank, which may' be of the character described in my prior 'Patent No. 885,450, dated April 21,1908. In this tank the bulk of the impurities, usually 90% or more of the total quantity, is'separated by sedimentation.

Thecomparatively clear, hot and gas-free plete. thesedimentation, or are filtered. A

suitable acid, preferably dilute phosphoric acid, is introduced into the juice flowing fromthe .first to, the second of these tanks, the acidbeing added in solution, in a continuous stream, and in proportion to the flow of the juice. The flow of acid may be convariable proportion thereto, subject to man the eliminator to a circulatin v trolled by any suitable device by the flow of the mainstream of juice, so as to bear aminual adjustment, control and regulation. The effect of the introduction of the acid at this pointis three-fold: (1') It effects a permanent decolorization of the juice, .as distinguished from the fugitive effect of sulfur ioxid or of phos horic acid introduced before separation o thebulk of the lime precipitate. (2) It markedly increases the efficiency of the second separating tank, and the small proportion of insoluble calcium phosphate formed by reaction with the excess of lime or dissolved calcium salts facilitates to a remarkable degree the separation by gravity of the minute and light materials whlch have escaped-sedimentation in the first separating tank. (3) It ermits correction of the efi'ects of overiming at a point where such correction can be secured without waste of acid by double decomposition with the precipitated calcium salts.

In the accompanying drawings I have illustrated more or less diagrammatically and in side elevation a plant for the defecation and decolorizing of cane juices in accordance with my'invention;

In saiddrawings A represents a gas-eliminator which may be of the type described in my prior application, Ser. No. 426,900,

above referred to. The juice from the crushing rolls, after treatment with lime and other appropriate reagents, enters the system through pipe 1 leading to a surface condenser 2 in the upper part of the eliminator. A pipe 3 conveys the juice from this condenser to a heater or digester B by which the solution is brought to a suitable temperature which may equal or exceed the atmospheric boiling point. From this heater the juice passes to a pipe at and adjustably-weighted pressure-reducing valve 5 to the interior of the eliminator A, which in the form shown comprises a closed tank having cylindrical sides and a converging bottom. A pipe 6 leads from the bottom of pump C which delivers the degasified juice through pipes 7, 8 and 9 to a continuous-flow separating tank E, which may be of the character described in my prior Patent No. 885,450, or of any other suitable type. In the elim-- inator A the heated juice enteringat 5 is' subjected to reduced pressure, obtained for example by a pipe connection 20 leading from the upper part of the eliminator to the vacuum pump, and under such reduced pressure the escape of the contained gases is tank E the bulk of the- The comparatively clear solution overflows through pipe 10 and passes by pipes 11 .to the second separating tank I receiving in its course between the tanks E .and F, through pipe 15, a regulated addition of dilute phosphoric acid. In tank F the decolorization of the juice, as Well as a com plete separation of the residual suspended matters, is effected, and the clear juice is permitted to flow directly through pipe 12 to the evaporating system. The precipitate settling to the bottom of the tank F may be discharged continuously or intermittently through pipe 13 to the mud tanks.

14 represents a washout connection common to the tanks E and F.

From the tank F the juice preferably flows through a strainer or filter the purpose of which is to remove any fiber or like material which may have passed through the separating tanks, and flows thence dlrect to the evaporating system.

I claimi 1. The method of separating suspended impurities from sugar juices in continuous flow, which consists in adding lime to the juice and heating it, separating the bulk of the resulting precipitate by gravity from the flowing body of juice, adding an acid precipitant for lime to the stream of partially clarified juice, and finally separating the residual suspended matters.

2. The method of separating suspended impurities from sugar juices in continuous flow, which consists in adding lime to the juice and heating it, separating the bulk of the resulting precipitate by gravity from the flowing body of juice, adding an acid precipitant for lime to the stream of partially clarified juice, and finally separating the residual suspended matters by gravity from the flowing body of juice. m

In testimony whereof, I afiix my signature in presence of two witnesses.

EUGENE W. DEMING.

, WVitnesses:

J. RANDOLPH Lone, TH. DENKWITZ. 

